The condition of the TM joint in dentistry has usually been assumed to be normal or adapted after occlusal appliance therapy. It is possible to increase the predictability of our restorative treatment as well as have a more accurate prognosis discussion with our patients if we can classify the condition of TM joints based on the anatomic condition of condyle and the disk.
There are two main TM joint classifications used today in dentistry. This article will describe the classification system designed by Clyde Wilkes  and outline the 5 different stages of TM joints in the Wilkes Classification System.
The first stage is the early stage. The early stage presents clinically with no significant mechanical symptoms, other than reciprocal clicking (early in opening movement, late in closing movement, and soft in intensity). There is no pain or limitation of motion in this stage. The radiologic presentation was a slight forward displacement with good anatomical contour of disk, and normal tomograms. The surgical presentation is normal anatomical form, slight anterior displacement, and passive incoordination (clicking) demonstrable.
The second stage is the early/intermediate stage. The early/intermediate stage presents clinically with few episodes of pain, occasional joint tenderness and related temporal headaches. This stage has beginning major mechanical problems with an increase in intensity of clicking sounds and joint sounds later in opening movement. This stage also presents with beginning transient subluxations or joint catching and locking.
The radiologic presentation is with slight forward displacement, slight thickening of posterior edge or beginning anatomical deformity of disk, and normal tomograms. The surgical presentation in this stage is anterior disk displacement early with anatomical deformity consisting of a slight to mild thickening of posterior edge and well-defined central articulating area.
The third stage is the intermediate stage. The intermediate stage presents clinically with multiple episodes of pain, joint tenderness, temporal headaches. There are major mechanical symptoms such as transient catching, locking and sustained locking (closed locks), restriction of motion, and difficulty (pain) with function in this stage.
The radiologic presentation is anterior displacement with significant anatomical deformity with prolapse of the disk (moderate to marked thickening of posterior edge) and normal tomograms. The surgical presentation is marked anatomical deformity with displacement, variable adhesions (anterior, lateral, and posterior recesses), and no hard-tissue changes.
The fourth stage is the Intermediate/late stage. This stage presents clinically with chronicity with variable and episodic pain, headaches, variable restriction of motion, and undulating course.
The radiologic presentation is an increase in severity over intermediate stage with abnormal tomograms, and early to moderate degenerative remodeling hard-tissue changes. The surgical presentation consists of an increase in severity over the intermediate stage with hard tissue degenerative remodeling changes of both bearing surfaces, osteophytic projections, multiple adhesions (lateral, anterior, and posterior recesses), and no perforation of disk or attachment.
The fifth and final stage is the late stage. The clinical presentation is characterized by crepitus on examination with scraping, grating and grinding symptoms. There is variable and episodic pain with a chronic restriction of motion, and difficulty with function.
The radiologic presentation consists of anterior displacement, perforation with simultaneous filling of upper and lower compartments, filling defects and gross anatomical deformity of disk and hard tissues. There are abnormal tomograms as described, and essentially degenerative arthritic changes. The surgical presentation had gross degenerative changes of disk and hard tissues and perforation of posterior attachments. There are erosions of bearing surfaces, and multiple adhesions equivalent to degenerative arthritis (sclerosis, flattening, anvil-shaped condyle, osteophytic projections, and subcortical cystic formation).
Dr. Jim McKee, Spear Resident Faculty
 Wilkes, C. Internal Derangements of the Temporomandibular Joint. Arch Otolaryngol Head Neck Surg